1. Field of the Invention
The present invention relates to audio signal processing using, for example, a moving picture expert group (MPEG)-4, that is, audio signal encoding and decoding, and more particularly, to an apparatus, method, and medium for processing an audio signal using a correlation between bands.
2. Description of the Related Art
In a conventional method of processing an audio signal, such as perceptual noise substitution (PNS) which is used as an MPEG-4 audio coding tool, an audio signal can be effectively processed at a low bit rate such as 64 kbps/stereo, but sound quality is degraded at a high bit rate. In the conventional method, in particular, when a transient audio signal is processed, sound quality is more degraded. In addition, in the conventional method, the audio signal is encoded by reducing an audio frequency bandwidth since the number of available bits is small. In this case, since the audio frequency bandwidth is reduced, sound quality is more degraded.